[Elecraft] CM-500

[Bill Frantz]

As I noted in my report, which deliberately reached no 
conclusions, just the facts ma'am, the microphone stopped 
working when I removed the "bias" on the K3. So it needs that 
power. Well, electret microphones certainly need power to run 
their internal amplifiers. Some other microphones (e.g. 
condensor) also need power, which is why pro audio systems have 
phantom power over their audio cables.

It very probably isn't a dynamic mic, although someone might 
build a dynamic mic with a built-in amplifier which would only 
work with external power. YMMV!

However, given the electret microphones are very cheap and are 
good quality, I'd bet on electret.

For more information and a fun read, see <https://en.wikipedia.org/wiki/Microphone>.

73 Bill AE6JV

On 11/8/20 at 4:27 AM, jim at audiosystemsgroup.com (Jim Brown) wrote:

>On 11/7/2020 2:42 PM, Bill Frantz wrote:
>>The packaging said (in part), "Dynamic Microphone for Active Musicians"
>
>The sales/marketing department, usually ignorant of what 
>they're selling, wrote that drivel you're reading, which is 
>intended simply to sell more of whatever they're selling.
>
>The CM500 has had an ELECTRET mic as far back as 2008, when 
>W6XU, another audio professional, arranged a group purchase for 
>your Bay Area contesting club. It DOES need Bias, which most 
>modern rigs provide on one pin of their mic connector. Simply 
>adding a resistor of suitable value (in the range of 5-10KOhms) 
>between that pin and the mic input pin, provides bias suitable 
>for most electret mics.
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